A teacher at an East Oakland elementary school has been placed on leave as officials investigate accusations that two of his second-grade students engaged in oral sex in the classroom and that some ran around without their clothes on, a district spokesman said Friday.

Oakland Unified School District officials said the allegations involved students in a classroom at Markham Elementary School, and that the reported conduct happened sometime last week. A student came forward with details of the incidents Wednesday, district spokesman Troy Flint said.

"Acting on early findings, the investigation is leading us to believe that these details have merit," Flint said.

The district placed the teacher on paid administrative leave, Flint said. The teacher told officials that he was unaware of either incident. His name was not released.

Although details of the incidents remain sketchy, authorities said they are investigating reports that a girl and a boy engaged in oral sex in the classroom, Flint said.

In a separate case, two students disrobed "at least partially" in the same classroom and became disruptive, school officials said. It was not immediately clear whether the same two students were involved in both incidents.

Letter to parents

Principal Pam Booker sent a letter to parents Thursday saying the parents of the students reportedly involved in the incidents had been contacted.

She said the school prides itself on providing a "safe learning environment for all of our children, and the events as reported represent an unacceptable lack of supervision."

Alan Saunders, whose 7-year-old nephew is in the classroom where the incidents allegedly occurred, defended the teacher as he arrived Friday to pick the boy up from school.

"No kind of weird problems, good vibes from him. He's a real good teacher," Saunders said.

Some of the students in the class have behavioral problems, and at times the teacher has to separate children who are acting up from other students, Saunders said.

In the coatroom?

The children involved in the alleged sex incident "could have gone around the corner," Saunders said. "They have coatrooms and other stuff in every room. It wasn't like he (the teacher) was at fault. It's not the teachers' responsibility to babysit the kids. They're there to teach them."

Flint said young children "have a natural curiosity about the human body, and they're prone to exploration. But, of course, we have to work with children to make sure they understand that there's a proper time, place and manner to do so."

If the incidents are confirmed to have taken place, Flint said, it will be important to tell the children that "they are not at fault" and that any blame lies with teachers and other adults and their "egregious lack of supervision."

Monique Wells, 28, has a son in a different second-grade class at the school.

"What kind of parents do they have?" Wells asked Friday. "That's what goes through my mind, because if these are second-graders, they really don't know anything about sex."

Very rare

Experts in child sexual abuse said it's highly unusual for children that young to engage in sexual acts of any kind. When children are only 7 or 8 years old, they're typically starting to explore their bodies and learn about what feels good to them, but they're far too young to have any interest in sex with others.

Crawford-Jakubiak said investigators should find out whether one child initiated the contact, and what that child had been exposed to outside the classroom. He said it's possible one of the children has been sexually abused and needs help.

"I'm more concerned about specific issues going on with specific kids," Crawford-Jakubiak said, "as opposed to generalizing and saying that this happened because there's too much sex on television."